This invention relates to improved methods and apparatus for producing frozen food products which are coated with batter.
The conventional method of producing frozen battered food products, such as for example individual portions of fish, other seafood, or the like, is to first apply the batter to the food product in raw form, then partially cook the batter to set it to a non-flowing condition, and then ultimately freeze the coated product for sale in frozen form. The batter may be applied by advancing the food products on a conveyor through a container of batter, with the products after leaving this conveyor being dropped into a body of hot cooking oil for attaining the partial cooking effect. The food products may be pre-frozen before application of the batter and remain cold even after a short interval in the hot oil, so that only the batter is partially cooked. The final freezing step may be attained by any conventional freezing process, including if desired, the spraying of carbon dioxide snow onto the upper surface of the coated product while moving along a final convenyor.
Such use of partial cooking of the batter for setting it to a non-flowing condition has several decided disadvantages. In the first place, the process is very wasteful of energy, in that the coating of batter on the food product is first heated to a high temperature for partial cooking, and then immediately frozen to a very low temperature for ultimate packaging. Both of these steps require the expenditure of a substantial amount of energy, much of which is wasted since the elevation of temperature for the partial cooking step is completely counterproductive insofar as the final freezing step is concerned. Whatever energy is added to heat the product during the partial cooking must be removed in the final freezing step. Further, oil absorbed by the batter during the partial cooking process may detract from the quality of the ultimate product by virtue of the tendency for the oil to become rancid. In addition, the types of batters which can be fried at the extremely high temperatures and in the very short periods of time required in this conventional process are more complex than would be desired, and can not be the types of very inexpensive and simple batters which are usable under other circumstances. These batters which must be employed for the discussed process can not be very thin batters because of the tendency for excessive crumb formation in the partial frying process, nor can they be crisp batters, which are extremely fragile and can not be shipped after partial frying and freezing.
Canadian Pat. No. 823,139 issued September 16, 1969 refers to a process in which a battered food product may be frozen while the batter is raw, by immersion of the coated product in liquid nitrogen. This process, however, would be extremely expensive, and would have the disadvantage of producing an undesirably violet reaction at the time of immersion of the product in the liquid, tending to cause much of the liquid batter to be lost from the surface of the product and accumulate in the bottom of the cooling liquid tank.